Note: Descriptions are shown in the official language in which they were submitted.
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MOTION AND VIBRATION CUING SYSTEM
FIELD OF THE INVENTION
[0001] This
invention relates to motion simulators for aircraft, land vehicles
and water vehicles, and, more particularly, to a motion and vibration cuing
system for
providing vibratory, impulse, onset and sustained motion cuing wherein the
movement of motion seats is coupled to the movement of a frame assembly upon
which the motion seats are mounted.
BACKGROUND OF THE INVENTION
[0002] One
of the most common motion simulation systems in use today are
flight simulators which re-create aircraft flight and different aspects of the
flight
environment. Flight simulators are employed for flight training, the design
and
development of aircraft, control handling evaluation and other purposes.
Depending
on the purpose of a particular device, flight simulators can range in
complexity from
PC- laptop models to full flight simulators employing replicas of an aircraft
cockpit
including controls, aircraft systems and wide-field outside-world (OTW) visual
systems all mounted on six degree-of-freedom motion platforms which move in
response to control commands from the cockpit and external aerodynamic forces.
These motions include three linear movements, namely heave (up and down),
surge
(fore and aft) and sway (side-to-side), and, three rotational movements
including
pitch (rotation about the sway axis), yaw (rotation about the heave axis) and
roll
(rotation about the surge axis).
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25 [0003]
Current full flight simulators capable of meeting the so-called Level D
standard promulgated by the Federal Aviation Administration in the U.S.,
employ a
motion platform supported by six hydraulic or electric jacks. The motion
platform, in
turn, mounts a vibration platform upon which the replica cockpit of the
aircraft is
supported. The shaft of each jack, which is extended and retracted to obtain
the
30 desired motion, has a limited degree of travel and therefore the
concept of
acceleration onset cuing is relied upon to provide the user of the system with
the
desired sensation of motion for a particular aircraft maneuver or external
aerodynamic forces applied to the aircraft.
Onset cuing provides an initial
acceleration of the cockpit which closely replicates that of an aircraft in
flight, but
35 then the jack movement is decreased to zero after which time the
motion platform is
reset to a neutral position at a rate below that of the sensory threshold of
the user.
This technique has proven effective in simulating the six degrees-of-freedom
of
motion noted above. Vibration, on the other hand, which may result from rough
weather, blade rotation, out-of-balance rotor, rotor gearbox malfunctions and
other
40 causes, is simulated by the vibration platform positioned between
the motion platform
and cockpit.
[0004]
Significant limitations of current full flight simulators of the type
described above include their extreme physical size and substantial cost.
Typically,
full flight simulators require a motion envelope of about fifty feet in width,
fifty feet
45 in length and forty feet in height, with the size of the unit itself
being about twenty
feet wide, twenty-five feet long and twenty-five feet in height. A huge
facility is
required to house such simulators, and it is challenging and expensive to
install
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systems of such size and complexity. Further, full flight simulators typically
cost
between one and three million dollars (US), not including the cost of the
cockpit
50 control and OTW systems.
SUMMARY OF THE INVENTION
[0005] This
invention is directed to a motion and vibration cuing system
particularly intended for aircraft, but also useful for land vehicles and
water vehicles,
in which vibratory, impulse, onset and/or sustained motion cuing are provided
by a
55 frame assembly capable of producing vibration and six degrees-of-
freedom of motion
in combination with one or more motion seats which produce surge, sway, heave
and
roll motions. In the particular application of this invention for use in
aircraft
simulation, the system herein supports a simulated cockpit that may include
flight
controls, other aircraft systems and an OTW system.
60 [0006] In
one presently preferred embodiment, the system of this invention
includes a host computer coupled to a control computer and to the
instrumentation of
the particular vehicle whose motion is to be simulated, such as the cockpit
controls of
an aircraft. In response to operation of aircraft instrumentation, for
example, the host
computer outputs a host control signal to the control computer. The control
65 computer, in turn, is coupled to one or more motion seats mounted
atop the frame
assembly and to six frame actuators which support the frame assembly. An input
command signal from the control computer is provided to both the motion seats
and
the frame actuators which combine to closely replicate the tactile and visual
sensations that would be experienced by a pilot during a desired maneuver.
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70 [0007] The frame actuators that support the frame assembly are
effective to
produce six degrees-of-freedom of motion, including surge, sway, heave, roll,
pitch
and yaw, as well as vibration. The motion seat(s) produce surge, sway, heave
and roll
motions. Collectively, the frame actuators and motion seat(s) provide the
pilot with
the sensation of movement through his or her tactile interface with the motion
seat, as
75 well as a visual indication of the corresponding movement of the cockpit
created by
the actuators acting on the frame assembly, in order to closely replicate the
maneuver
which the user is performing using the instrumentation of the aircraft and/or
any
external aerodynamic forces being applied to the aircraft.
DESCRIPTION OF THE DRAWINGS
80 [0008] The structure, operation and advantages of this invention will
become
further apparent upon consideration of the following drawings taken in
conjunction
with the accompanying drawings, wherein:
[0009] Fig. 1 is a perspective view of a preferred embodiment of the
motion
and vibration cuing system of this invention;
85 [0010] Fig. 2 is a view similar to Fig. 1 except with the motion
seats and top
plate of the frame assembly removed;
[0011] Fig. 3 is a view similar to Fig. 2 except with the frame
assembly
removed;
[0012] Fig. 4 is a perspective view of an actuator of this invention;
90 [0013] Fig. 5 is a perspective view of an isolator used herein;
[0014] Fig. 6 is a schematic block diagram of the control system of
this
invention;
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[0015]
Fig. 7 is a schematic illustration of a drive controller for a frame
actuator herein; and
95 [0016] Fig. 8
is a view of the six degrees-of-freedom of motion that are
provided by the actuators of this invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017]
Referring initially to Figs. 1 and 6, a motion and vibration cuing
system 10 according to this invention is illustrated. The system 10 is adapted
for use
100 as part
of motion simulation system (not shown) for a particular type of vehicle. For
purposes of the present discussion, a full flight simulation system for
aircraft is
described herein but it should be understood that the system 10 may be
employed
with land vehicles and/or water vehicles. Further, the term "aircraft" is
meant to
broadly refer to fixed wing, rotary and hover craft.
105 [0018]
Full flight simulation systems may include a cockpit with highly
detailed replications of all of the flight controls and aircraft systems of a
particular
type of aircraft, as well as an OTW system which provides the user or pilot
with a
visual indication of what he or she would be seeing during flight. All of
these
components are commercially available and their details form no part of this
110
invention and are therefore not discussed herein. As schematically depicted in
Fig. 6
and discussed in detail below, the full flight simulator system includes a
host
computer 12 coupled to the cockpit controls or instrumentation 14 that a pilot
would
operate to perform different maneuvers with the aircraft, e.g. takeoff,
landing,
banking etc. The system 10 of this invention is coupled to the host computer
12 via a
115 control
computer 16 in order to provide a pilot with the sensations of movement and
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the visual indications associated with such maneuvers. Details of the
components of
system 10 are described below, followed by a discussion of the operation of
system
10.
[0019]
Referring now to Figs. 1-5, the system 10 comprises a frame assembly
120 18
which mounts a pilot motion seat 20 and a co-pilot motion seat 22. The frame
assembly 18, in turn, is supported by six frame actuators 24a-f and four
isolators 26a-
d which rest upon a base pad 28. Each of these elements of the system 10 is
described separately below.
[0020]
Each of the pilot and co-pilot motion seats 20, 22 includes a seat pan
125 30,
a back pan 32, a head rest 34 and a seat belt 36. Seat actuators (not shown)
are
capable of moving the motion seats 20, 22 to simulate surge, sway, heave and
roll
motions of an aircraft during flight. Fig. 8 provides a schematic illustration
of the six
degrees-of-freedom of motion which the motion seats 20, 22, combined with the
frame assembly 18, are capable of simulating. Details of the actuators and
other
130 structure for moving the motion seats 20, 22 form no part of this
invention and are not
discussed herein.
[0021] The
frame assembly 18 is best shown in Fig. 2. It comprises a support
structure 38, a sub-frame 40 and a number of vertical legs 42 which
interconnect the
support structure 38 and sub-frame 40 to form an essentially one-piece
construction.
135 The support structure 38 includes a series of spaced stringers 44
which extend
generally parallel to the surge axis depicted in Fig. 8. The stringers 44
connect to
cross bars 46, and/or to perimeter bars 48 forming the periphery of the
support
structure 38. Preferably, the sub-frame 40 comprises a forward plate 50, an
aft plate
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52, opposed side plates 54 and 56 connected between the forward and aft plates
50,
140 52 and a cross plate 58 extending between the side plates 54, 56. A
top plate 60 is
affixed over the support structure 38, as seen in Fig. 1, to which the motion
seats 20,
22 are attached. For purposes of the present discussion, the terms "forward"
and "aft"
are intended to refer to the orientation of the system 10 shown in the Figs.
wherein
the motion seats 20, 22 face the forward portion or forward end of the system
10 and
145 the opposite direction is the aft portion or aft end of the system 10.
[0022] As
noted above, the frame assembly 18 is supported by six frame
actuators 24a-f and four isolators 26a-d, which, in turn, rest atop the base
pad 28,
Referring in particular to Figs. 2 and 3, the base pad 28 has the same general
shape as
the sub-frame 40, including a forward plate 62, an aft plate 64, opposed side
plates 66
150 and 68
and a back plate 70 that connects to the ends of the side plates 66, 68,
Preferably, side-by-side channels 72 and 74 extend between the front plate 62
and the
back plate 70. The frame actuators 24a-f are arranged in pairs as illustrated
in Fig. 3,
and all of the frame actuators 24a-f and isolators 26a-d are affixed to one of
five
mounting plates 76a-e secured to the base pad 28, Specifically, frame
actuators 24a
155 and
24b are located on either side of an isolator 26a atop a mounting plate 76a
which
is affixed to the side plate 66 of base pad 28 proximate the forward end of
the frame
assembly 18, Similarly, a mounting plate 76b affixed to the side plate 68 of
base pad
28 supports isolator 26b positioned between frame actuators 24c and 24d at the
forward end of the frame assembly 18 opposite the frame actuators 24a and 24b.
The
160 remaining two frame actuators 24e and 24f straddle the channels 72,
74, in the middle
of the frame assembly 18 at its ail end, and are connected atop a mounting
plate 76c
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affixed to the aft plate 64. The frame actuators 26e, 26f are positioned
between the
third isolator 26c resting atop mounting plate 76d affixed to side plate 68,
and the
fourth isolator 26d which is connected to the side plate 66 by a mounting
plate 76e.
165 [0023] In one
preferred embodiment, the frame actuators 24a-f are
commercially available from the FxlarTM Corporation of Chanhassen, Minnesota
under Model No. GSX30, Part No. GSX30-0302-XCM-CT1-238-E13-AR-L3
Actuator. Each frame actuator 24a-f employs a servo motor (not shown) having a
power connection 78 and a brake connection 80. The frame actuators 24a-f are
170 equipped with an absolute encoder 81, shown schematically in Fig.
7, having an
encoder connection 82. The frame actuators 24a-f are cooled by oil supplied
via
supply line 84 and withdrawn through a return line 86 which are connected to a
cooling rack assembly (not shown). Upper and lower limit switches 88, 90 are
provided for purposes .discussed below. The shaft 92 of each frame actuator
24a-f is
175 connected to a rod end 94 mounted to a frame interface plate 96
(See Fig. 3), and an
anti-rotation bracket 98 extends between the actuator housing 100 and shaft 92
to
ensure that the shaft 92 moves in a linear direction. The frame interface
plate 96 of
each frame actuator 24a-f is bolted or otherwise affixed to the sub-frame 40
of frame
assembly 18 to impart motion thereto as the shaft 92 is extended and
retracted. A
180 clevis 102 is provided at the base of frame actuators 24a-e which
connects to a pivot
block 104 affixed to one of the mounting plates 76a-f.
{0024] Each of the
isolators 26a-d, in one presently preferred embodiment, is
commercially available from Fii.estoneTM Industrial Products CoMpany, LLC of
Indianapolis, Indiana under Model Na. Air Mount 110, Part No. W01-358-7451.
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185 Each isolator 26a-d comprises an isolator support frame 106 which mounts a
pneumatic isolator 108. A frame interface plate 110 connects the pneumatic
isolator
108 to the frame assembly 18. The frame interface plate 110 of each isolator
26a-d is
bolted or otherwise affixed to the sub-frame 40 of frame assembly 18 to assist
in
dampening the motion of frame assembly 18 in response to operation of the
frame
190 actuators 24a-f,
[0025] Having described the structural components of system 10, its
operation
is discussed in more detail below. Initially, as noted above, it should be
understood
that the system of this invention 10 is capable of providing vibratory,
impulse, onset
and/or sustained motion cuing for a pilot operating the full flight simulator
with
195 which the system 10 is employed. Vibratory cues are low magnitude
repetitive
movements at frequencies below 25 I-1z to simulate rough weather, blade
rotation,
out-of-balance rotor, rotor gearbox malfunctions, other aircraft equipment
issues and
external aerodynamic forces applied to an aircraft during flight. Impulse cues
result
from one-time events such as bird strikes, landing gear extension and
retraction and
200 landings.
[0026] It must be recognized that the shaft 92 of each frame
actuator 24a-f
acting on the frame assembly 18, and the seat actuators which create movement
of the
motion seats 20, 22, have a limited length of linear travel, e,g. on the order
of about
0.5 inches (12.7 mm). Vibratory and impulse cues generally may be replicated
by
205 such a relatively short' linear motion of shaft 92, but a pilot
operating the full flight
simulator must be provided with the sensation of greater movement in
conducting
maneuvers such as take-off, landing, banking and the like. Onset cues are
vestibular
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in nature, and sustained cues are onset cues that are maintained for the
duration of a
given maneuver. The system 10 of this invention employs the principle of
210 acceleration onset cuing using the combination of the movement of
frame assembly
18 induced by actuators 24a-f, and movement of the motion seats 20, 22 induced
by
seat actuators associated with such seats 20, 22. See Fig. 6. Acceleration
onset cuing
replicates cockpit movement in the six degrees-of-freedom illustrated in Fig.
8, in
essentially three phases. Initial acceleration of the aircraft resulting from
the
215
performance of a particular maneuver is relatively closely replicated by the
system
10. Because the limit of travel of the actuator shafts 92 is quickly reached,
after
initial acceleration the shaft 92 movement is gradually decreased to zero,
e.g. the
"washout phase." The frame assembly 18 is then reset to a neutral position,
but at a
rate below the sensory threshold of the pilot. In this way, maneuvers that
would
220 produce relatively large movements of the aircraft can be replicatc:d with
frame
actuators 24a-f and seat actuators whose shafts 92 have a comparatively small
amount
of linear 92 travel.
[0027]
Combined and coordinated movement of the motion seats 20, 22 and
frame assembly 18 is important in order to impart accurate sensations of
movement,
225 and realistic visual representations, for a given maneuver. As
noted above, the
motion seats 20, 22 are capable of providing sway, heave, surge and roll
motions,
whereas the frame assembly is movable in six degrees-of-freedom plus
vibration, It
is not sufficient for the system 10 to only provide movement of the motion
seats 20,
22 during a bank maneuver, for example, since the position of the cockpit
controls
230 would
also change (tilt) during such maneuver. Consequently, the frame assembly 18
CA 02764671 2012-01-17
must be employed to provide a combined and coordinated movement with the
motion
seats 20, 22 in order to replicate a bank maneuver such that not only does the
pilot
feel the sensation of a bank motion from one of the motion seats 20 or 22 but
also
visualizes the cockpit controls tilting in the same direction and at the same
time as
235 they would in actual flight. The same is true for other maneuvers that can
be
performed by the aircraft.
[0028]
Referring now to Figs. 6 and 7, operation of the system 10 is
controlled in response to host command signals from the host computer 12. For
example, assuming a pilot operating the cockpit or vehicle instrumentation 14
wishes
240 to perform a banking maneuver, the system 10 must react and provide
the pilot with
the sensations of movement associated with such a maneuver, e.g. both tactile
and
visual. An Ethernet connection 112 is provided between the host computer 12
and
control computer 16 to transfer host computer signals representative of the
maneuver
being performed by the pilot. The control computer 16 is connected by a cable
114 to
245 a frame assembly motion drive enclosure 116, a pilot motion seat
drive enclosure 118
and a co-pilot motion seat drive enclosure 120. The cable 114 may be a fiber
optic,
Ethernet, controller-area network (CAN) bus or an analog cable. Each of these
enclosures 116, 118 and 120 contains a number of drive controllers 122,
schematically depicted in Fig. 7. Enclosure 116 includes six drive controllers
122,
250 one for each of the frame actuators 24a-f as shown in box 124, and
each of the
enclosures 118, 120 contains four drive controllers 122 to accommodate the
four seat
actuators employed in the pilot motion seat 20 and the co-pilot motion sear 22
as
shown in boxes 126 and 128, respectively.
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[0029] The
drive controller 122 illustrated in Fig. 7 comprises a power section
255 130
and a control section 132. For purposes of illustration and discussion, one
drive
controller 122 and one frame actuator 24 are depicted in Fig. 7, although it
should be
understood that the discussion which follows is equally applicable to the
drive
controllers and seat actuators associated with the motion seats 20 and 22. The
power
section 130 of drive controller 122 receives a control voltage via line 134
and three
260 phase mains voltage via line 136. Three phase mains power is
supplied to the power
connection 78 of the actuator through line 138. An external actuator brake and
thermostat connection from the power section 130 to the brake connection 80 of
frame actuator 24 is provided through line 140.
[0030] An
input command signal from the control computer 16 is provided to
265 the
control section 132 of drive controller 122 through the cable 114, which
includes
a TX (transmit) connection 142 and an RX (receive) connection 144. The input
signal from control computer 16 is processed by firmware 146 in the control
section
132. The firmware 146 is coupled to the encoder connection 82 of a frame
actuator 24
via line 148. It uses a signal from such frame actuator 24, and applies
mathematical
270 equations, to determine the actuator rotation direction, velocity
and torque required to
best match the input command signal curve from the control computer 16. An
output
command from the control section 132 is thus generated which is input to the
power
section 130. In turn, the power section 130 employs the three-phase input
power and
the command data from the control section 132 to generate the necessary servo
motor
275 signal voltage for the operation of the actuator 24.
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[0031] Each
of the drive controllers 122 within the enclosures 116, 118 and
120 receives the input command signal from control computer 16 via the cable
114,
All of the drive controllers 122 function in the manner described above, and
their
operation is coordinated by the control computer 16 to create the desired
combined
280 movement of the frame assembly 18 and motion seat 20 and/or 22 for
replication of
the particular maneuver that the pilot desires to execute.
[0032] Prior
to and during system operation, the control computer 16
monitors the status of all connected drive controllers 122. In the event of an
error or
fault in any of the drive controllers 122, the control computer 16 halts all
motion of
285 the system 10 and transmits a fault code to the host computer 14
via the Ethernet
connection 112. Other safety features of the system include the use of upper
and
lower limit switches 88 and 90 to monitor the extent of linear movement of the
actuator shafts 92, and accelerometers (not shown) are located on the frame
assembly
18 to sense its motion. In the event predetermined limits of movement of the
shafts
290 92 or frame assembly 18 are reached, motion of the system 10 is
shut down and an
error message generated.
[0033] An
important advantage of the system 10 of this invention is that it
allows full flight simulators to be compact in physical size compared to prior
art
devices. The frame actuators 24a-f and isolators 26a-d are directly connected
to the
295 frame assembly 18, which, in turn, directly mounts the motion seats
20, 22, Unlike
prior art systems which employ a motion platform to generate six degrees-of-
freedom
of motion, and a separate vibration platform to produce vibration, a single
frame
assembly 18 to which the motion seats 20, 22 are directly mounted collectively
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produce both the desired six degrees-of-freedom of motion and vibration, This
300 dramatically reduces the physical size and expense of the system 10
compared to the
prior art, without sacrificing performance.
[0034] , While the invention has been described with reference to a
preferred
embodiment, it should be understood by those skilled in the art that various
changes
may be made and equivalents substituted for elements thereof without departing
from
305 the scope of the invention, In addition, many modifications may be made
to adapt a
particular situation or material to the teachings of the invention without
departing
from the essential scope thereof
[0035] For example, it is contemplated that in some applications of
the system
no isolators 26a-d would be required for dampening the motion of the frame
310 assembly 18. The need for isolators 26a-d depends on the overall weight
of the frame
assembly 18 and motion seats 20, 22, and/or other factors.
[0036] Therefore, it is intended that the invention not be limited
to the
particular embodiment disclosed as the best mode contemplated for carrying out
this
invention, but that the invention will include all embodiments falling within
the scope
315 of the appended claims,
